The problem with putting more guns on it is that it's going to get heavier and heavier.
Well, yes, hence the Gravite.
Anyway, whilst I'm not locked in, I'm going to put down my votes for now:
Research Credit Design:
GGG-12 (1): NUKE9.13
Regular Design:
GHMG-12 (1): Taricus
Gravite (1): NUKE9.13
E: This is an example of the sort of thing I'm talking about with flying warships:
KU-XX Flying Dreadnaught: It is a well known fact that he who holds the high ground automatically wins. Well, that might be an exaggeration, but it's definitely an advantage. What to do when there is no high ground to hold? Create your own!
The KU-XX is a massive flying weapons platform. Some might initially think it to be an airship, but make no mistake- this is not a lighter-than-air craft. The six GA1 cannons on the sides (three each), the many AA machine guns, and the thick steel armour ensure that this is a dense craft, more similar to an ocean-going vessel than a conventional aerial vehicle. Indeed, the thing would probably crack tarmac rather than float into the sky, were it not for the large Aligned Gravite antiweights making it just about able to sit on an airstrip on its massive retractable landing gear. To actually become airborne, even more lift is required, and for this the KU-XX contains 3 Molten Gravite lifting engines- large vats of Gravite that are heated to melting point using electrical heaters, then subjected to intense downwards radiation, creating truly preposterous amounts of anti-gravity. Propulsion is provided by six massive propellers, each powered by large Gavrilium Engines (with electrical heaters). Three huge Gavrilium engines hooked up to generators provide power for the lifting engines and other systems.
Two lifting engines are enough to keep the KU-XX airborne if one fails. The armour is thickest on the bottom, for obvious reasons, although it is not exactly thin on the top and sides.
There is a landing pad on top of the ship(?) for small VTOL aircraft.
The KU-XX measures 90*12*12 meters, with a crew complement of 100.
Something like that, anyway. Something unlikely to be less than Very Expensive until we've developed our economy quite considerably- indeed, it'd might even be a National Effort in the first few turns. But even a NE could be useful, I think.
Mind you, it's basically a destroyer in terms of size, so it depends on how the GM chooses to interpret the cost category it falls into- like, you know, infantry weapons are costed differently from tanks, tanks are costed differently from ships. In the aeroplane category this would be extremely expensive, in the ship category it wouldn't be so bad.